// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/inspector/search-util.h"

#include "src/inspector/protocol/Protocol.h"
#include "src/inspector/v8-inspector-impl.h"
#include "src/inspector/v8-inspector-session-impl.h"
#include "src/inspector/v8-regex.h"

namespace v8_inspector {

namespace {

    String16 findMagicComment(const String16& content, const String16& name,
        bool multiline)
    {
        DCHECK_EQ(String16::kNotFound, name.find("="));
        size_t length = content.length();
        size_t nameLength = name.length();

        size_t pos = length;
        size_t equalSignPos = 0;
        size_t closingCommentPos = 0;
        while (true) {
            pos = content.reverseFind(name, pos);
            if (pos == String16::kNotFound)
                return String16();

            // Check for a /\/[\/*][@#][ \t]/ regexp (length of 4) before found name.
            if (pos < 4)
                return String16();
            pos -= 4;
            if (content[pos] != '/')
                continue;
            if ((content[pos + 1] != '/' || multiline) && (content[pos + 1] != '*' || !multiline))
                continue;
            if (content[pos + 2] != '#' && content[pos + 2] != '@')
                continue;
            if (content[pos + 3] != ' ' && content[pos + 3] != '\t')
                continue;
            equalSignPos = pos + 4 + nameLength;
            if (equalSignPos < length && content[equalSignPos] != '=')
                continue;
            if (multiline) {
                closingCommentPos = content.find("*/", equalSignPos + 1);
                if (closingCommentPos == String16::kNotFound)
                    return String16();
            }

            break;
        }

        DCHECK(equalSignPos);
        DCHECK(!multiline || closingCommentPos);
        size_t urlPos = equalSignPos + 1;
        String16 match = multiline
            ? content.substring(urlPos, closingCommentPos - urlPos)
            : content.substring(urlPos);

        size_t newLine = match.find("\n");
        if (newLine != String16::kNotFound)
            match = match.substring(0, newLine);
        match = match.stripWhiteSpace();

        for (size_t i = 0; i < match.length(); ++i) {
            UChar c = match[i];
            if (c == '"' || c == '\'' || c == ' ' || c == '\t')
                return "";
        }

        return match;
    }

    String16 createSearchRegexSource(const String16& text)
    {
        String16Builder result;

        for (size_t i = 0; i < text.length(); i++) {
            UChar c = text[i];
            if (c == '[' || c == ']' || c == '(' || c == ')' || c == '{' || c == '}' || c == '+' || c == '-' || c == '*' || c == '.' || c == ',' || c == '?' || c == '\\' || c == '^' || c == '$' || c == '|') {
                result.append('\\');
            }
            result.append(c);
        }

        return result.toString();
    }

    std::unique_ptr<std::vector<size_t>> lineEndings(const String16& text)
    {
        std::unique_ptr<std::vector<size_t>> result(new std::vector<size_t>());

        const String16 lineEndString = "\n";
        size_t start = 0;
        while (start < text.length()) {
            size_t lineEnd = text.find(lineEndString, start);
            if (lineEnd == String16::kNotFound)
                break;

            result->push_back(lineEnd);
            start = lineEnd + 1;
        }
        result->push_back(text.length());

        return result;
    }

    std::vector<std::pair<int, String16>> scriptRegexpMatchesByLines(
        const V8Regex& regex, const String16& text)
    {
        std::vector<std::pair<int, String16>> result;
        if (text.isEmpty())
            return result;

        std::unique_ptr<std::vector<size_t>> endings(lineEndings(text));
        size_t size = endings->size();
        size_t start = 0;
        for (size_t lineNumber = 0; lineNumber < size; ++lineNumber) {
            size_t lineEnd = endings->at(lineNumber);
            String16 line = text.substring(start, lineEnd - start);
            if (line.length() && line[line.length() - 1] == '\r')
                line = line.substring(0, line.length() - 1);

            int matchLength;
            if (regex.match(line, 0, &matchLength) != -1)
                result.push_back(std::pair<int, String16>(lineNumber, line));

            start = lineEnd + 1;
        }
        return result;
    }

    std::unique_ptr<protocol::Debugger::SearchMatch> buildObjectForSearchMatch(
        int lineNumber, const String16& lineContent)
    {
        return protocol::Debugger::SearchMatch::create()
            .setLineNumber(lineNumber)
            .setLineContent(lineContent)
            .build();
    }

    std::unique_ptr<V8Regex> createSearchRegex(V8InspectorImpl* inspector,
        const String16& query,
        bool caseSensitive, bool isRegex)
    {
        String16 regexSource = isRegex ? query : createSearchRegexSource(query);
        return std::unique_ptr<V8Regex>(
            new V8Regex(inspector, regexSource, caseSensitive));
    }

} // namespace

std::vector<std::unique_ptr<protocol::Debugger::SearchMatch>>
searchInTextByLinesImpl(V8InspectorSession* session, const String16& text,
    const String16& query, const bool caseSensitive,
    const bool isRegex)
{
    std::unique_ptr<V8Regex> regex = createSearchRegex(
        static_cast<V8InspectorSessionImpl*>(session)->inspector(), query,
        caseSensitive, isRegex);
    std::vector<std::pair<int, String16>> matches = scriptRegexpMatchesByLines(*regex.get(), text);

    std::vector<std::unique_ptr<protocol::Debugger::SearchMatch>> result;
    for (const auto& match : matches)
        result.push_back(buildObjectForSearchMatch(match.first, match.second));
    return result;
}

String16 findSourceURL(const String16& content, bool multiline)
{
    return findMagicComment(content, "sourceURL", multiline);
}

String16 findSourceMapURL(const String16& content, bool multiline)
{
    return findMagicComment(content, "sourceMappingURL", multiline);
}

} // namespace v8_inspector
